Camera back-piece



(No Model.)

J. P. HEIN.

CAMEEA BACK PIECE.

No. 427,321. Patented May 6, 1890.

UNITED STATES PATENT OEEICE.

JENS F. HEIN, OF BOSTON, MASSACHUSETTS.

CAMERA BACK-PIECE.

SPECIFICATION forming part of Letters Patent No. 427,321, dated May 6, 1890.

Application filed April 27, 1889. Serial No. 308,789. (No model.)

To all whom it may concern,.-

Be it known that I, .TENS F. HEIN, of Boston, county of Suffolk, State ot Massachusetts, have invented an Improvement in Oamera Back-Pieces, of which the following description, in connection with the accompanying drawings, is a speciiication, like letters on the drawings representing like parts.

In photographic cameras the frame which carries the focusing-screen-usnally a plate j of ground glass-is attached to the back-piece of the camera by four links, which constitute hinges, whereby said frame may be moved away from the back-piece for the insertion of the plate-holder between them. The focusing-frame near one end has pins or proj ections which are acted upon by springs attached to the back-piece. In use it frequently happens that these. springs weaken or there is wear between the springs and their pins, and as a result, the springs acting as they do upon one end only ot' the frame, said frame is not always firmly and squarely seated upon the back-piece, as it should be for proper focusing; and when the plate-holder is inserted between the said frame and back-plate the springs do not always set the same squarely in its seat, which is very essential to good photography.

In my improved back-piece the focusingframe is provided near each end with pins -or projections with which co-operate the opposite free ends of two springs, the latter being attached to the back-piece at a central point, the connection between the springs and pins or projections being such as to enable the pins to take a yielding bearing in the springs.

By mounting the focusing-frame as described it is free to yield for the ready insertion of the plate-holder, and at the same time the springs by acting upon both ends of the focusing-'frame always set the same squarely upon the back-piece, as well as the plate-holder, when the same is placed between the said focusing-frame and the back-piece.

Figure l is a face view of my improved back-piece and its attached focusing-frame; Fig. 2, a side elevation of the same, and Figs. 3 and 4 details to be referred to.

A represents the back-piece of a camera of usual construction. Two springs h Z) are secured to the said back-piece, preferably at a central point, by means of screws 2. The outer or free ends l1 h2 of said springs act respectively upon the pins or projections c" c2 of the focusing-trame c, provided with a suitable ground-glass or other screen cx. The ends h of the springs h h are bent to encircle the pins or projections c', in order that the frame may always be seated in the same position upon the back-piece. The opposite ends b2 of said springs simply bear upon their pins or projections c2, to thus allow Afor the shortening of the springs as they are bent. Two screws S-one at each side of the central attaching-screws 2-serve as limiting-stops to prevent undue bending of the springs.

The focusing-frame c is provided with suitable lugs or ears c3, to assist the operator in lifting that end of the frame away from the back-piece for the insertion of the end of the plate-holder e, as shown in Fig. After the end ot the plate-holder has been inserted, as shown in Fig. 3, it may readily and easily be shoved entirely in, as shown in Fig. LL, the focusing-frame being lifted before it and nally resting upon it, in which position, still acted upon at each end by the springs h b, it holds said plate-holder firmly and squarely in place. The plate-holder is provided with suitablyinclined stops 5, one of which, according as one or the other side of the plate-holder is to be used, enters or drops into a recess G in the back-piece, as shown in Fig. 4, thus preventing withdrawal of the plateholder. The end of the focusing-trame c is beveled at c to facilitate the insertion ot the plate-holder. lVhen it is desired to withdraw the plateholder, the end of the frame c may be lifted 'far enough' for the disengagement of the stop 5 from the recess 6, when the holder may be withdrawn, the frame gradually seating itself upon the back-piece after it. (See Fig. 3.) It will thus be seen that the trame c, acted upon as it is at each end by the springs h h, must always, even though the springs may weaken or wear, seat the frame or the plateholder' evenly and squarely upon the backpiece. It will also be seen that the operation IOO of inserting and removing` the plate-holder is greatly facilitated.

I do not desire to limit myself to the particular kind of spring' shown, as any other kind of spring which would bear upon both ends of the frame at once would come Within the scope of this invention.

I claim- The back-piece A and the focusing-frame c, combined with the springs b, rigidly secured to said baclvpiece at or near the center of said springs, the outer or free ends of the springs acting upon portions of said focusing- 

